The subject matter described herein relates generally to methods for monitoring environmental barrier coating (EBC) conditions, and more specifically, to methods for monitoring temperature and erosion of EBCs using phosphor thermometry.
Higher operating temperatures for gas turbine engines are continuously sought in order to increase their efficiency. However, as operating temperatures increase, the high temperature durability of the components of the engine must correspondingly increase. In known gas turbine engines, ceramic materials containing silicon, such as those comprising silicon carbide as a matrix material and/or as a reinforcing material are used as substrate materials for higher temperature applications. These silicon-containing matrix/reinforcing materials are commonly referred to as ceramic matrix composites (CMCs). CMCs facilitate decreasing the weight yet maintaining the strength and durability of gas turbine engine components comprising such substrates, such as turbine components comprising airfoils (e.g., compressors, turbines, vanes, etc.), combustors, and other turbine components for which reduced weight is desirable.
As operating temperatures increase, the high temperature durability of CMC materials must also correspondingly increase. In many applications, a protective coating is beneficial or required for CMCs. Such coatings provide environmental protection by inhibiting the major mechanism for degradation of CMC materials in a corrosive water-containing environment, namely, the formation of volatile silicon monoxide and silicon hydroxide products. Consequently, a necessary requirement of an EBC system is stability in high temperature environments containing water vapors. In order to assess EBC systems in such environments, it is necessary to measure online or real-time component temperature and to monitor EBC health. However, measurement of the temperature of objects in a remote, non-contact, manner or on moving parts is very difficult.